Honing apparatus



June 19, 1962 c. A. BALMAN 3,039,234

HONING APPARATUS Filed May 21. 1959 130 Reservoir j- 34 4972;: 4 ,I/Z'ra? CZAQEMCE 11. B40144;

INVENTOR.

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3,039,234 Patented June 19, 1962 ice 3,039,234 HONING APPARATUS Clarence A. Balman, La Verne, Calif., assignor to General Dynamics Corporation, San Diego, Calif., a corporation of Delaware Filed May 21, 1959, Ser. No. 814,818 12 Claims. (Cl. 51-2) This invention relates generally to methods and apparatus for honing, abrading or polishing the internal surfaces of passages; more particularly, it relates to a method and apparatus for honing, abrading or polishing the internal surfaces of passages by reciprocating an abrasiveladen fluid through the passages.

The problems encountered when abrading, honing or polishing the interiors of passages are well known. When no great degree of smoothness or polish is required, interior surfaces can be satisfactorily formed by boring and reaming. However, in some instances, specifications may require that the inner passages of a part be very smooth and highly polished. An example of such a part is an hydraulic manifold containing a network of small, interconnecting internal passages. Generally, the surfaces of bored and reamed interiors can be completely smoothed and highly polished by the use of bones. However, as is well known, hones cannot be readily used in all passages because of mechanical and structural limitations. It is apparent from the foregoing that a method and apparatus for abrading, honing or polishing the internal surfaces of passages is needed. One known method of treating the interiors of hollow objects utilizes a spinning mandrel equipped with annular vanes to forcefully propel an abrasive-laden fluid against the inner surfaces to remove scale. In this method, the operation must be stopped as soon as the scale is removed because the abrasive particles will begin gouging the interior, leaving scarred surfaces. This method, therefore, is not suitable for abrading, honing or polishing the inner surfaces of bored and reamed interiors.

In another method, a stream of abrasive-laden fluid is forcefully directed from a nozzle against the inner surfaces of hollow objects. This method is normally used to remove scale, slag and the like from the interiors of boilers and furnaces. Since the abrasive fluid impinges upon (strikes) the inner surfaces with suflicient force to remove scale and slag, the operation must be observed closely and stopped when feasible to limit the amount of gouging and scarring by the abrasive particles. This method, too, is not suitable for honing, abrading or polishing the internal surfaces of passages.

In still another method, a helical stream of abrasiveladen fluid is directed against the inner surfaces of a hollow object by rotation of a helically grooved shaft coaxially positioned within the object. However, this method is inherently restricted to treatment of comparatively straight passages and is not adaptable to abrading or honing the inner surfaces of non-linear or intersecting passages. Further, in order to reverse hte flow of abrasive slurry through the passages, the operation must be stopped and the position of the work piece reversed.

In another method, a motor-driven helical rotor revolving coaxially within a helical stator maintains a positive pressure to force abrasive slurry through the inner passages of a work piece. Here again, the operation must be stopped in order to reverse the flow of slurry through the work piece to provide uniform treatment of the inner surfaces, especially at the corners of intersecting passages. In this method, either the motor or the work piece may be reversed to effect redirection of the abrasive slurry.

It is therefore an object of this invention to provide a new and improved method of abrading, honing or polishing internal surfaces.

lil

An object of the present invention is to provide a novel method and apparatus for abrading, honing or polishing internal surfaces by the reciprocal flow of an abrasiveladen fluid.

Another object of this invention is the provision of a method of abrading, honing or polishing internal surfaces wherein abrasive-laden fluid is reciprocated by application of suction and pressure.

It is another object of the present invention to provide a novel method and apparatus for abrading, honing or polishing intersecting passages and nonlinear passages by reciprocation of an abrasive-laden fluid.

Another object of this invention is the provision of a novel apparatus wherein the velocity and volume of a reciprocating abrasive-laden fluid are controllable for abrading, honing or polishing selected corners of intersecting passages or selected surfaces of nonlinear (curved) passages.

Other objects, features and advantages of the present invention will become apparent to those skilled in the art from a consideration of the following description, the appended claims, and the accompanying drawings, in which:

FIGURE 1 is an elevational view, partially in section, of a preferred embodiment of the apparatus of the present invention;

FIGURE 2 is a perspective view, partially in section, showing the recirculator element of the apparatus of FIGURE 1;

FIGURE 3 is a perspective view of a part containing intersecting passages to be abraded, honed or polished;

FIGURES 4 and 5 are illustrations of the abrading, honing or polishing of intersecting passages in accordance with the present invention; and

FIGURE 6 is an elevational view, partially in section, of a modified form of the apparatus according to the present invention.

Referring to the drawings, and particularly to FIGURE 1, a preferred embodiment of the present invention is shown as including a pair of pumps or pressure transfer devices 10, 12, each divided into separate compartments 14, 16 and 18, 20 respectively, by flexible diaphragms 22, 24 which are clamped securely by locking rings 26, 28. The diaphragms 22, 24 are preferably fabricated of elastomeric materials. Fluid couplings 30, 32 interconnect compartments 16, 20 with recirculators 34, 36 respectively, which are connected by conduits 38, 40 to a workpiece 42 which is positioned in a fixture 44. A tank 46 is connected to abrasive slurry compartments 16 and 20 through tubes 48, 50 and control valves 52, 54 respectively. Cylinder-s 56, 58 are respectively connected to compartments i4, 13 of the pumps through tubes 60, 62. Valves 64, 66 are respectively mounted on compartments 14, 18 to permit additional or removal of hydraulic fluid, as required. Vacuum gages 68, i0 and pressure gages 72, 74 are attached to cylinders 56, 58 respectively.

Pistons 76 and 78 are slidably positioned in cylinders 5 6, 80 respectively and both are secured to a rod 82. Also affixed to rod 82 is a switch actuator 84 in contact with two limit switches 86 and 88 The limit switches are electrically connected to a junction box 90 which is connected to a standard source of voltage (not shown). A similar arrangement is provided on the opposite side of the apparatus shown in FIGURE 1. Pistons 92, 94 in cylinders 58, 96 respectively, and a switch actuator 98 are afiixed to a rod 100. The switch actuator is in contact with two limit switches 102, 104 which are electrically connected to junction box 90.

Attached to one end of cylinder 80 is a divided conduit 106 which connects to a solenoid-operated, 4-way, 2-position, hydraulic control valve 108 through a flow control valve 110 and a gate valve 112 in one branch, and through a gate valve 114 and a flow control valve 116 in another branch. Attached to the opposite end of cylinder 80 is another divided conduit 118 which connects to solenoidoperated valve 108 through a flow control valve 120 and a gate valve 122 in one branch, and through a gate valve 124 and a flow control valve 126 in another branch. All the gate valves and flow control valves are adjustable to control rate of flow through them. In accordance with standard practice, the arrow indicators shown with the flow control valves indicate that fluid flow against the arrows is full or free and that fiow with the arrows is restricted. A hydraulic fluid return line 128 interconnects one side of solenoid-operated valve 108 to a hydraulic fluid reservoir 130. From another side of valve 108 a high pressure coupling 132 extends through and adjustable flow control-bypass valve 134, to a pump 136 driven by an electric motor 138. Flow controLbyp'ass valve 134 is connected by coupling 140- to return line 128. Bypass valve 134 is normally adjusted to pass fluid below a predetermined pressure. When the pressure is exceeded, the fluid is bypassed through coupling 140 into return line 128 to reservoir 130.

A similar arrangement of elements is provided on the opposite side. Attached to cylinder 96 are divided conduits 142, 144 which connect to a solenoid-operated, 4-way, 2-position hydraulic control valve 146. One branch of conduit 142 extends through a flow control valve 148 and a gate valve 150, and another branch extends through a gate valve 152 and a flow control valve 154. A branch of conduit 144 extends through a flow control valve 156 and a gate valve 158, and another branch extends through a gate valve 160 and a flow control valve 162. The gate valves and flow control valves are adjustable to control the rate of flow through them. An hydraulic fluid return line 164 leads from one side of solenoid-operated valve 146 and interconnects with return line 128 to reservoir 130. From another side of valve 146 a high pressure coupling 166 extends through an adjustable flow control-bypass valve 168 and interconnects with high pressure coupling 132 to pump 136. Flow control-bypass valve 168 is connected by coupling 170 to return line 164. Bypass valve 168 is adjustable in the same manner as bypass valve 134 described above.

In FIGURE 2, the recirculator 34 of FIGURE 1 is shown in detail. Recirculator 34 which is identical to recirculator 36, comprises a cover plate 172, a base plate 174, which are secured together through appropriate bolt holes 176, 178 by appropriate bolts (not shown). Cover 172 has an inlet hole 180, an outlet hole 182, and an angularly disposed groove 184. Base plate 174 contains an angled groove 186 and a parallel groove 188.

In FIGURE 3 workpiece 42 of FIGURE 1 is shown in detail. The workpiece, or part to be internally honed, has intersecting passages 190. Workpiece 42 is secured by appropriate clamps 192, 194 to fixture 44. Fluid couplings 38, are shown in operating position.

To prepare the apparatus of FIGURE 1 for operation in accordance with the method of the present invention, tank 46 is filled with abrasive slurry, preferably water containing abrasive particles. The abrasive-laden fluid, or slurry, is supplied to lower compartments 16, 20 of pumps 10, 12 through tubes 48, 50 by opening valves 52, 54, respectively. Slurry also fills fluid couplings 30, 3 2, recirculators 34, 36 and conduits 3 8, 40. Valves 52, 54 are closed when the filling operation is completed.

Suitable hydraulic fluid is injected into upper compartments 14, 18 of pumps 10, 12' through opened fill and bleed valves 64, 66 from any convenient source (not shown). When compartments 14, 18 become filled, the hydraulic fluid flows upward through tubes 60, 62 into cylinders 56, 58 respectively. When the filling operation is completed, valves 64, 66 are closed.

Reservoir 130, cylinders 80, 96 and all hydraulic couplings connected thereto are also filled with suitable hydraulic fluid from any convenient source (not shown).

After the apparatus has been filled with abrasive slurry and hydraulic fluid it can then be operated in three different fashions or modes, depending upon certain valve settings that will be explained later. It can be seen from FIGURE 1 that upward movement of piston 76 causes a temporary pressure drop in cylinder 56 that causes diaphragm 2.2 to move upward, drawing abrasive slurry from workpiece 42'. Also, when piston 92 moves downward it causes a temporary pressure increase in cylinder 58 that causes diaphragm 2.0 to move downward, forcing abrasive slurry through workpiece 42. As will be seen, the piston 76 rises when piston 92 is making its downward stroke, and vice versa.

If the drop in pressure causing one diaphragm to be pulled upward is greater in magnitude than the increase in pressure causing the opposite diaphragm to move downward, then the abrasive slurry is drawn or sucked through the workpiece. This is one mode of operation that can be achieved, and will be referred to as the suction mode. When operating in this mode, the action of the abrasive slurry is concentrated against the inside radii of intersecting passages in the workpiece, as shown in FIGURE 4.

A second mode of operation is that in which one diaphragm moves down under pressure greater than that which causes the opposite diaphragm to move up. When this occurs the abrasive slurry is forced or pushed through the workpiece, and the abrasive action is concentrated at the outside radii of intersecting passages in the workpiece as shown in FIGURE 5. This particular mode of operation will be referred to as the pushing mode.

And finally, the third mode of operation, the normal mode, is that in which the magnitude of the downward and upward pressures on the two diaphragms are the same. When operating in this normal mode, the action of the abrasive slurry is distributed substantially evenly at the passageway intersections.

In order to start the apparatus operating in any of the above modes however, it is first necessary to activate the electrical system. This is done by turning on a switch (not shown) in junction box 90. This turns on motor 138 for pump 136, and applies voltage to the limit switches 86, 88, 102, 104 and valves 108, 146.

Now, by referring to FIGURE 1, the action of this electrical system can be clearly followed. The piston 78 is shown ready for its downward stroke and piston 94 is ready for its upward stroke. Reversal of the piston strokes, at the ends thereof, is automatically initiated and maintained by the closing of limit switches 86and 104 at the end of one-half cycle and by the closing of limit switches 88 and 102 at the end of the next one-half cycle. Switch actuators 84 and 98, respectively mounted on rods 82, 100, move with the piston strokes and are adjusted to close the appropriate limit switches at the end of each stroke by automatic activation of the switch levers. Closing the limit switches completes the electric circuits to solenoid-operated valves 108, 146 where the incoming hydraulic fluid flowing through high pressure couplings 132, 166 is alternately directed to opposite ends of cylinders 80, 96 to drive pistons 78, 94 respectively.

From this it can be seen that the operation of the electrical system and hydraulic system are closely integrated and dependent on each other. Only the hydraulic system, however, is varied to prescribe the particular mode of operation that will be followed, i.e. suction, pushing or normal. This will be seen from the following description of the hydraulic system operation.

In response to electric motor 138, pump 136 forces hydraulic fluid through high pressure coupling 1 32 into interconnecting high pressure coupling 166, and through flow control-bypass valve 168 to solenoid operated valve 146. Valve 146 is energized by closed limit switch 104, causing the hydraulic fluid to flow into divided conduit 144. At the same time, high pressure coupling 132 has carried hydraulic fluid to solenoid operated valve 108. Valve 108 is energized by limit switch 86, causing hydraulic fluid to flow into divided conduit 106. Thus, at this point, piston 78 is ready to start down in response to fluid from divided conduit 106, and piston 94 is ready to start up in response to fluid from divided conduit 144.

Now, it is to be recalled that the suction mode of operation can be achieved by having each piston subjected to more pressure on its upstroke than the opposite piston is subjected to on its downstroke. Therefore, in the instant situation, fluid conduit 144 must supply more pressure to piston 94 than conduit 106 supplies to piston 73. This is accomplished by having gate valve 112 of divided conduit 106 set to close when fluid attempts to flow into cylinder 80, and gate valve 114 set to remain open continually. Thus the fluid in divided conduit 106 can only flow into cylinder 80 through flow control valve 116 and open gate valve 114. The position of the arrow for 110W control valve 116 indicates that any flow into cylinder 80 will be restricted. As a result, fluid flowing into cylinder 80 to cause piston 78 to move downward is restricted, or impeded.

At the same time, the gate valve 158 of divided conduit 144 is set to close when fluid attempts to flow into cylinder 96. Fluid flowing into cylinder 96 thus passes through flow control valve 162 and gate valve 160, which is set to remain open continually. The arrow of flow control valve 162 shows that such flow into cylinder 96, causing piston 94 to move upward, is unrestricted. Since the fluid supplied to both pistons comes from the same source, i.e. pump 2136, and since the flow causing one piston to move down is restricted, and the flow causing the other piston to move up is unrestricted, the pressure on the upward moving piston is greater than the pressure on the downwardmoving piston. This produces the suction mode of operation previously described.

To completely describe one whole cycle of this mode, however, the motion of pistons 94 and 78 will be followed until they have returned to their positions as shown in FIGURE 1. Thus, as piston 94 moves upward in response to unrestricted fluid flow from conduit 144, the fluid above piston 94 returns to the reservoir through conduit 164, solenoid controlled valve 146, and the upper divided conduit 142. Gate valve 150, just like gate valve 112, is set to let fluid flow from the cylinder but not into the cylinder. Gate valve 152, just like gate valve 114, is set to be continuously open. The fluid flowing from cylinder 96 thus follows two paths, one restricted and the other unrestricted.

When piston 94 reaches the end of its upward stroke, limit switch 102 is activated and it, in turn, switches valve 146 so that pressurized fluid will be supplied to the upper divided conduit, conduit =142. Piston 94 is now ready to start a downward stroke.

At the same time, piston 78 has moved downward and is ready to start an upward stroke. In moving down, piston 78 caused fluid to return to the reservoir via line 12 8, solenoid operated valve 108, and divided conduit 118. The gate valve 122, just as gate valve 158, is set to close when fluid attempts to flow into the piston cylinder but remains open when fluid is flowing out of the cylinder. The gate valve 124, just as gate valve 160, is set to be open continually. Fluid flowing from cylinder 80 on the pistons downward stroke therefore returns to the reservoir through both passages of divided conduit 118, one passage being restricted and the other being unrestricted. At the end of the piston stroke limit switch 88 is activated and it, in turn, switches solenoid operated valve 108 so that pressurized fluid will be supplied to piston 78 through divided conduit 118.

With the pistons in this position, i.e. piston 78 down and piston 94 up, they will repeat the second half of the cycle, again with the upward moving piston (now 78) being subjected to the greater pressure, until their positions as shown in FIGURE 1 are attained.

To recapitulate, this suction mode of operation is achieved by having the valves in the lower divided conduits 144 and 118 set so that fluid flow into their respective piston cylinders is unrestricted. At the same time, the valves in the upper divided conduits 142 and 106 are set so as to restrict fluid flow into their respective piston cylinders. Fluid flow from the cylinders in returning to the reservoir is through both paths of the respective divided conduits.

If the pushing mode of operation is now recalled, it will be remembered that it requires the pressure pushing one piston down to be greater than the pressure pushing the other piston up. To accomplish this the valves in the upper divided conduits 106 and 142 are set so as to permit fluid to flow into their respective cylinders unrestricted. The valves in the lower divided conduits are set to restrict fluid flow into their respective cylinders. The gate valve settings for this pushing mode of operation are thus as follows: Gate valves and 124 set to let fluid pass from their respective piston cylinders but not into their respective piston cylinders. Gate valves 158 and 122 continually open; gate valves 150 and 110 continually open; and gate valves 152 and 114 set to let fluid pass from their respective piston cylinders but not into their respective piston cylinders.

And the third mode of operation, the norma mode, is produced by having the pressure pushing one piston down equal the pressure pushing the other piston up. There are a number of gate valve settings or adjustments which will produce the normal mode, which settings should now appear obvious from the previous description of operation of the apparatus.

It is also apparent from the previous description of operation that the action of the abrasive slurry can be concentrated at certain points merely by selection of the proper mode of operation. As an aid to the abrading or honing action of the slurry, the recirculators 34 and 36 have been provided. They are positioned as the lowest elements of the slurry system, where the abrasive particles in the slurry may settle when the apparatus is stopped. When the apparatus is restarted, the settled particles are rapidly remixed with the slurry fluid, which is reciprocatingly swirled through the recirculators. This action can best be understood by referring to FIGURE 2. Slurry fluid, urged by movement of the diaphragms of pumps 10, 12, flows downwardly through inlet hole in cover plate 172 to angled groove 186 in base plate 174 where abrasive particles have accumulated. The particles are remixed with the incoming slurry fluid and the resultant mixture flows upwardly to angularly disposed groove 184 in cover 172. From groove 184 the swirling mixture is directed downwardly to angled groove 188 where additional abrasive particles have accumulated. The slurry mixture recombines with the particles and then flows upwardly through outlet hole 182. During alternate half cycles of the apparatus of FIGURE 1, flow is reversed through the recirculators. The mixture then flows downwardly through hole 182 to groove 188 in base plate 174 where it is directed upwardly to groove 184 in cover 172. From groove 184 the mixture is directed downwardly to groove 186 and thence upwardly through hole 180 in the cover. The recirculators 34 and 36 thus provide a means for keeping the abrasive particles distributed through the slurry, independent of the mode of operation of the apparatus.

As to one of the modes of operation, FIGURE 6 shows a modified form of the apparatus capable of operating only in the normal mode. In this figure the apparatus is shown as including the pumps 10, 12, each divided, as previously explained, into separate compartments 14, 16 and 18, 20 respectively, by flexible diaphragms 22, 24 which are clamped securely by locking rings 26, 28. Fluid couplings 30, 32 interconnect compartments 16, 20 with workpiece 42 which is positioned in fixtures 44. Fluid couplings 200, 202 are attached to compartments 14, 18 respectively and also connect to the ends of cylinder 204. Piston 206, slidably positionedin cylinder 2%, is aflixed to a rod 208 which engages an arm 216 attached to an electric motor 212. To prepare the apparatus of FIGURE 6 for operation, abrasive-laden fluid, or slurry, is supplied to compartments 16, of pumps 10, 12 respectively, from any convenient source (not shown). Slurry also fills fluid couplings 3t), 32 to workpiece 42. Cylinder 204, fluid couplings 269, 202, and compartments 14, 18 of pumps 10, 12 respectively, are filled with suitable hydraulic fluid from any convenient source (not shown). Operation is commenced by activating a switch (not shown) to start motor 212. Operating at a predetermined speed, the motor actuates arm 21th attached to rod 208 and drives piston 206 back and forth in cylinder 204. Moving toward fluid coupling 200, piston 206 forces hydraulic fluid through coupling 200 into compartment 14 of pump 10. Flexible diaphragm 22 is thus deformed, or lowered, thereby urging abrasive slurry from compartment 16 through coupling and workpiece 42. Simultaneously, in the present cycle, the movement of piston 206 urges hydraulic fluid from compartment 18 of pump 12 through coupling 292 into cylinder 204. Flexible diaphragm 24 of pump 12 is thus stretched, or raised, drawing slurry through workpiece 42 into coupling 32 and compartment 20. Thus, a pushing force and an equal coacting suction force have been effected to urge abrasive slurry through the workpiece.

When piston 2% reverses and moves toward fluid coupling 202 during the alternate cycle, hydraulic fluid is forced with equal pressure through coupling 202 into chamber 18 of pump 12. Flexible diaphragm 24 is thus deformed, or lowered, thereby urging abrasive slurry from compartment 29 through coupling 32 and workpiece 42. Simultaneously, as in the cycle previously explained, the movement of piston 206 urges hydraulic fluid from compartment 14 of pump it} through coupling 200 into cylinder 2%. Flexible diaphragm 22 is thus stretched, or raised, drawing slurry through workpiece 42 into coupling 3t) and compartment 16.

It will thus be appreciated that a uniform reciprocating flow of abrasive slurry is eflected by the apparatus of FIGURE 6 to abrade, hone or polish the internal passages of the workpiece.

The recirculators 34 and 36 are not incorporated in the apparatus of FIGURE 6 but could be easily inserted if desired. This only points up the fact that although specific embodiments of the present invention have been described and illustrated, it is understood that the same are by way of illustration and example only; and it is also understood that the invention is not limited thereto, as many variations will be apparent to those versed in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims.

I claim:

1. An apparatus for finishing the interiors of passages in a workpiece, said apparatus comprising two pumping chambers, a diaphragm disposed in each pumping chamber, said diaphragms separating each pumping chamber into a first compartment for containing an abrasive slurry and a second compartment, said first compartment of each pumping chamber connected to a selected passage of said workpiece, and means connected to the second compartment of each pumping chamber for applying pressure and suction to said diaphragms thereby causing movement of said abrasive slun'y through said selected passage of said workpiece.

2. An apparatus for finishing the interiors of passages in a workpiece, said apparatus comprising two pumping chambers, a diaphragm disposed in each pumping chamber, said diaphragms separating each pumping chamber into a first compartment for containing an abrasive slurry and a second compartment for containing a fluid, said first compartment of each pumping chamber connected by individual slurry conduits to a selected passage of said workpiece, and means connected to the second compartmen-ts of said pumping chambers for alternately and simultaneously applying pressure and suction to said' diaphragms, thereby causing reciprocal movement of said abrasive slurry through said selected passage of said workpiece.

3. An apparatus for finishing the interiors of passages in a workpiece, said apparatus comprising two pumping chambers, a diaphragm disposed in each pumping chamher, said diaphragms separating each pumping chamber into a first compartment for containing an abrasive slurry and a second compartment for containing a fluid, a tank for containing abrasive slurry, said tank connected to each said first compartment by conduits, valves associated with said conduits for controlling flow of abrasive slurry from said tank to said first compartments, said first compartment of each pumping chamber connected by individual slurry conduits to a selected passage of said workpiece, at least one of said slurry conduits containing an abrasive particle settling trap recirculator member, and means connected to the second compartments of said pumping chambers for alternately and simultaneously applying pressure and suction to said diaphragms, thereby causing reciprocal movement of said abrasive slurry through said selected passage of said workpiece.

4. An apparatus for finishing the interiors of passages in a workpiece, said apparatus comprising two pumping chambers, a diaphragm disposed in each pumping chamher, said diaphragms separating each pumping chamber into' a first compartment for containing an abrasive slurry and a second compartment for containing a fluid, each of said first compartments connected to a selected passage of said workpiece, two piston cylinders for containing fluid, said second compartments each having a fluid connection to one of said piston cylinders, said second compartments connected to different piston cylinders, a pumping piston disposed in each piston cylinder, each pumping piston adapted for movement in a pressure stroke to force fluid into the second compartment connected to its respective piston cylinder, each pumping piston adapted for movement in a suction stroke to draw fluid i rom the second compartment connected to its respective piston cylinder, and actuating means connected to said pumping pistons for alternately and simultane ously moving one pumping piston in a pressure stroke and the other pumping piston in a suction stroke.

5. The apparatus of claim 4 in which the actuating means comprises a source for fluid, fluid pressure producing means connected to said source for fluid, first and second 4-way 2-position electrically responsive con- 'trol valves connected to said pressure producing means, first and second primary piston cylinders each having a first and second end, the first and second ends of said first primary piston cylinder connected to said first electrically responsive control valve, the first and second ends of said second primary piston cylinder connected to said second electrically responsive control valve, first and second primary pistons disposed within the respective primary piston cylinders, linking means connecting said first primary piston to one of said pumping pistons, linking means connecting said second primary piston to the other pumping piston, and electrical means for controlling said electrically responsive control valves whereby pressurized fluid flow to said primary piston cylinders is controlled.

6. The apparatus of claim 4 in which the actuating means comprises a source for fluid, fluid pressure pro ducing means connected to said source foTfluid, first and second 4-way 2-position electrically responsive control valves connected to said pressure producing means, first and second primary piston cylinders each having a first and second end, the first and second ends of said first primary piston cylinder connected to said first electrically responsive control valve, the first and second ends of said second primary piston cylinder connected to said second electrically responsive control valve, said control valves selectively connecting said first and second piston ends to said fluid pressure producing means in response to electrical signals, first and second primary pistons disposed within the respective primary piston cylinders, linking means connecting said first primary piston to one of said pumping pistons, linking means connecting said second primary piston to the other pumping piston, said pumping pistons caused to move in accordance with said primary pistons by said linking means, and electrical means for causing said electrically responsive control valves to alternately and substantially simultaneously connect the first end of one primary piston cylinder and the second end of the other primary piston cylinder to said fluid pressure producing means.

7. An apparatus for finishing the interiors of passages in a workpiece, said apparatus comprising two pumping chambers, a diaphragm disposed in each pumping chamher, said diaphragms separating each pumping chamber into a first compartment for containing an abrasive slurry and a second compartment for containing a fluid, each of said first compartments connected to a selected passage of said workpiece, two piston cylinders for containing fluid, said second compartments each having a fluid connection to one of said piston cylinders, said second compartments connected to different piston cylinders, a pumping piston disposed in each piston cylinder, each pumping piston adapted for movement in a pressure stroke to force fluid into the second compartment connected to its respective piston cylinder, each pumping piston adapted for movement in a suction stroke to draw fluid from the second compartment connected to its respective piston cylinder, first and second primary piston cylinders each having a first and second end portion, said end portions each containing a fluid port, a primary piston disposed in each primary piston cylinder, said primary pistons adapted for movement in response to pressurized fluid admitted to their respective primary piston cylinders through said fluid ports, each said pumping piston connected to a primary piston to move in accordance therewith, means for supplying pressurized fluid, first and second fluid control valves connected to said means, said ports of said first primary piston cylinder connected to said first control valve, said ports of said second primary piston cylinder connected to said second fluid control valve, and said fluid control valves adapted to selectively connect one port of each primary piston cylinder to said means for supplying pressurized fluid and one port of each primary piston cylinder to a low pressure fluid line.

8. An apparatus for finishing the interiors of passages in a workpiece, said apparatus comprising two pumping chambers, a diaphragm disposed in each pumping chamber, said diaphragms separating each pumping chamber into a first compartment for containing an abrasive slurry and a second compartment for containing a fluid, each of said first compartments connected to a selected passage of said workpiece, two piston cylinders for containing fluid, said second compartments each having a fluid connection to one of said piston cylinders, said second compartments connected to ditferent piston cylinders, a pumping piston disposed in each piston cylinder, each pumping piston adapted for movement in a pressure stroke to force fluid into the second compartment connected to its respective piston cylinder, each pumping piston adapted for movement in a suction stroke to draw fluid from the second compartment connected to its respective piston cylinder, first and second primary piston cylinders each having a first and second end portion, said end portions each containing a fluid port, a primary piston disposed in each primary piston cylinder, said primary pistons adapted for movement in response to pressurized fluid admitted to their respective primary piston cylinders through said fluid ports, each said pumping piston connected to a primary piston to move in ac- 10 cordance therewith, means for supplying pressurized fluid, a low pressure fluid outlet line, first and second fluid control valves connected to said means for supplying pressurized fluid and to said low pressure fluid outlet, conduits connecting said end ports of said first primary piston cylinder to said first fluid control valve, conduits connecting said end ports of said second primary piston cylinder to said second control valve, said control valves adapted to selectively connect one port of each primarypiston cylinder to said means for supplying pressurized fluid and one port of each primary piston to said low pressure fluid outlet, and means associated with each conduit connected between a control valve and primary piston cylinder for selectively restricting flow of fluid therethrough.

9. An apparatus for finishing the interiors of passages in a workpiece, said apparatus comprising two pumping chambers, a diaphragm disposed in each pumping cham her, said diaphragms separating each pumping chamber into a first compartment for containing an abrasive slurry and a second compartment for containing a fluid, each of said first compartments connected to a selected passage of said workpiece, two piston cylinders for containing fluid, said second compartments each having a fluid connection to one of said piston cylinders, said second compartments connected to different piston cylinders, a pumping piston disposed in each piston cylinder, each pumping piston adapted for movement in a pressure stroke to force fluid into the second compartment connected to its respective piston cylinder, each pumping piston adapted for movement in a suction stroke to draw fluid from the second compartment connected to its respective piston cylinder, first and second primary piston cylinders each having a first and second end portion, said end portions each containing a fluid port, a primary piston disposed in each primary piston cylinder, said primary pistons adapted for movement in response to pressurized fluid admitted to their respective primary piston cylinders through said fluid ports, each said pumping piston connected to a primary piston to move in accordance therewith, means for supplying pressurized fluid, a low pressure fluid outlet line, first and second 4-way 2 position electrically responsive fluid control valves connected to said means for supplying pressurized fluid and to said low pressure fluid outlet, fluid conduits connected between each end port of said first primary piston cylinder and said first control valve, fluid conduits connected between each end port of said second primary piston cylinder and said second control valve, said control valves selectively connecting said fluid conduits to said fluid pressure producing means and said low pressure fluid outlet line in response to electrical signals, and electrical means for directing said control valves to alternately and substantially simultaneously connect the fluid conduit of said first end port of one primary piston cylinder and the fluid conduit of said second end port of the other primary piston cylinder to said fluid pressure producing means while the other end ports fluid conduits are connected to said low pressure fluid outlet line.

10. The apparatus of claim 9 in which each of the fluid conduits connected between a control valve and a primary piston cylinder port is divided into first and second branches, each branch of each fluid conduit including a flow control valve and a gate valve, said flow control valves and gate valves arranged to permit greater fluid flow into said first end ports of said primary piston cylinders than into said second end ports thereof, and said flow control valves and gate valves concurrently arranged to permit substantially unrestricted flow of fluid from said ports of said primary piston cylinders.

11. The apparatus of claim 9 in which each of the fluid conduits connected between a control valve and a primary piston cylinder port is divided into first and second branches, each branch of each fluid conduit including a flow control valve and a gate valve, said flow control valves and gate valves arranged to permit greater fluid flow into said second end ports of said primary piston cylinders than into said first end ports thereof, and said flow control valves and gate valves concurrently ar- [ranged to permit substantially unrestricted flow of fluid 5 from said ports of said primary piston cylinders.

12. The apparatus of claim 9 in which each of the fluid conduits connected between a control valve and a primary piston cylinder port is divided into first and second branches, each branch of each fluid conduit includ- 10 ing a flow control valve and a gate valve, said flow control valves and gate valves arranged to permit substan- 11;? tialiy the same fluid flow into said first end ports of said primary piston cylinders as into said second end ports thereof, and said flow control valves and gate valves concurrently arranged to permit substantially unrestricted flow of fluid from sai d' -ports' of said primary piston cylinders.

References Cited in the file of this patent UNITED STATES PATENTS 

